The United States is condemning an outbreak of violence in eastern Ukraine, calling it the deadliest 24-hour period so far this year.

Ukraine’s military says nine soldiers have died in the east where Ukrainian forces and Russia-backed rebels have been fighting for more than three years.

State Department spokeswoman Heather Nauert says that five deaths were in clashes that appear to have been initiated by what she described as Russian-led forces.

Ten soldiers were also wounded and one was captured, according to the Ukrainian Ministry Defence. Two civilians were also reported wounded in Avdiivka on Wednesday morning.

Nauert said the US is asking the Russia-supported troops to abide by the terms of a ceasefire deal for eastern Ukraine that was signed in early 2015 but never fully implemented. The US has called on those forces to allow international monitors to have “full, safe, and unfettered” access to the conflict zone, Nauert said.

At least 20 Ukrainian soldiers have been killed and at least 35 more have been wounded in the first 20 days of July, according to Liveuamap.